I don't know of the specifics on this one, but in the UI/UX world it's rarely a good idea to "support both". They generally lead to bad looking UIs that "almost" work for everyone, but aren't a good fit for anyone.

A calendar that also lets you click on the displayed date [0] in order to type in the desired date is almost never disliked.

[0] By that, I mean a string somewhere on the widget like "2015-07-20", or however dates are displayed on the system.